SPTS Si DRIE
|Tool Name||SPTS Si DRIE|
|Staff Manager||Sam Azadi|
|Lab Location||Bay 2|
SPTS Rapier is an anisotropic dry etch tool. The tool uses Bosch Process to etch silicon with high selectivity and nearly vertical sidewalls. Bosch process consists of two steps: 1) Deposition of a passivation layer, using C4F8 gas. This passivation layer is a polymer that protects the sidewalls from being etched. 2) A nearly vertical plasma etch step using SF6. A bias is applied in the chamber that forces the ions to attack the surface vertically and etch through the passivation layer at the bottom of the trench, exposing the silicon underneath. That Si is then etched within the same step. The passivation layer is also deposited inside the chamber and the etch results in a layer of deposited polymer inside the chamber walls which makes it critical to run a cleaning recipe at the end of each etch run.
Shorter cycle times result in smoother sidewalls while longer cycle times achieve higher etch rate. The tool in QNF is connected to Ar, O2,N2, C4F8, and SF6 gases.
- Deep etching of Si
Etch masks allowed
- SiO2, SiNx, Al2O3, AlN
- No metal is allowed in the chamber!
Post etch sample cleaning procedure
We recommend an O2 plasma in a barrel asher for removal of residue of the passivation layer as well as remainder of resist mask.
The standard cleaning recipe is a 300 Watt O2 plasma for 1 hour, with 100 sccm O2 flow - see DE-02 tool page.